Research

Euplotes walks with a stochastic gait

Sensorimotor behavior in single cells

Single cells can display remarkably sophisticated, seemingly animal-like behaviors, orchestrating active processes far from thermodynamic equilibrium in order to carry out proper biological functions. While complex behaviors in animals, generally stemming from neural activity, have been extensively studied, we know comparatively little about the principles and mechanisms of cellular behavior. In individual cells, behaviors emerge directly from the joint action of chemical reactions, cellular architecture, and physical mechanisms and constraints within the cell and in its local environment. We are accumulating an increasingly sophisticated and detailed understanding of the molecular components of cells, but there remains great difficulty in translating this knowledge into understanding of how cells work.

How do cells control behavior? Put another way, how do cells decide what to do from one moment to the next and then properly execute these decisions? Furthermore, how do such capacities evolve? To answer these and related questions, I am combining theory from non-equilibrium physics and computer science with experiments investigating the sensorimotor and algorithmic behavior of ciliates (primarily Euplotes) and amoebae. This work is developing new tools, both theoretical and experimental, for interrogating the control of complex cellular behaviors while shedding new light on principles underlying cellular decision-making and behavior.

Biophysical principles of choanoflagellate self-organization

Principles of multicellular morphogenesis

Many organisms possess the remarkable capacity to reproducibly develop into 3D structures starting from a single cell. I am interested in both the mechanisms by which multicellular morphogenesis is accomplished and in how such capacities evolve. I am particularly interested in how the regulated interplay between active cellular processes and physical constraints gives rise to the robust generation of form.

During my PhD in Nicole King’s lab, I studied morphogenesis in choanoflagellates, the closest living relatives of animals (see Publications). By comparing and contrasting the biology of choanoflagellates (and other protistan relatives) with that of animals, we are beginning to learn more about the evolutionary origins of animal multicellularity, including the evolutionary origins of developmental morphogenesis. My dissertation work shed new light on the role of the interplay between cellular behavior and physical constraints in giving rise to reproducible morphogenetic processes (see Publications). While my work focused primarily on a couple of species of choanoflagellates, my interests extend broadly to principles of morphogenesis. Many protists have “simple” forms of multicellularity (in contrast to the “complex” multicellularity of plants, animals, and fungi), and my ongoing and future work aims to take comparative approaches, combining theory and experiments, to uncover principles of the regulation and evolution of morphogenesis.

A snapshot of protist diversity

Natural history of protists

Much of the diversity of protists remains completely uncharacterized. Just about any field sample might contain a cell that could lead to important insights into fundamental biological questions. Although genomic and transcriptomic approaches can provide an important window on microbes in the environment, there is no substitute for the relatively slow approaches of careful observation and cultivation of cells, particularly when it comes to protists where cellular structure and function are difficult if not impossible to infer from a genome or transcriptome alone. These points were made abundantly clear during my PhD when I had the good fortune to discover an exciting new species of choanoflagellate along with awesome former labmates and collaborators Tess Linden and Thibaut Brunet (see Publications). This new choanoflagellate was particularly exciting in that its cellular structure and behaviors provided new information for reconstructions of animal ancestors that existed before the evolution of coordinated function of specialized cell types.

My specific research interests may evolve, but I am always on the lookout for fascinating critters and the new questions they might inspire. In fact, many of my research directions have been influenced by observations made in the field. Even if I was not lucky enough to be employed as a scientist, I would still be scooping water to find and observe protists, and I feel incredibly lucky that I am able to incorporate this kind of work into my research program. To crib an inspirational quote from Louis Agassiz that I first encountered at the MBL, “study nature, not books.”